A Dynamic Simulation Method for a Gas Equipment System Based on Digital Twin Technology

Abstract

The present invention discloses a dynamic simulation method for a gas equipment system based on digital twin technology, including obtaining typical operating conditions of the gas equipment system, obtaining process design parameters of system equipment components, establishing a static simulation model of the gas equipment system based on digital twin technology, and inputting the obtained process design parameters of system equipment components; creating a dynamic simulation model of the gas equipment system; loading the automation control program of the gas equipment system onto a virtual simulator to form a closed-loop dynamic simulation platform; inputting the initial operating conditions of several typical operating conditions of the gas equipment system into the dynamic simulation model to generate operating result parameter information; generating adjustment strategy information, substituting the adjustment strategy information into the dynamic simulation model of the gas equipment system to obtain the optimal adjustment strategy of the gas equipment system, and adjusting the automation control program of the gas equipment system; having the advantages of accurate simulation effect, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG gas supply equipment systems, and in particular to a dynamic simulation method for a gas equipment system based on digital twin technology. Background Art

[0002] A gas equipment system refers to a gas equipment system that supplies gas with suitable pressure and temperature required by gas-using equipment. A gas equipment system generally includes equipment such as an LNG storage tank, an LNG deep well pump or a submersible pump, a gas compressor, a high-pressure LNG reciprocating pump, a low-pressure LNG evaporator, a high-pressure LNG evaporator, a gas cooler, a low-pressure gas buffer tank, and a high-pressure gas buffer tank. Usually, the entire gas equipment system must be installed before the entire gas equipment system can be tested. If problems are found, rework and adjustment are required.

[0003] Digital twin technology, as a cutting-edge scientific and technological innovation, gradually emerged in the early 21st century. Digital twin technology is also known as digital mapping or digital mirroring, which refers to using tools such as principle, mechanism, and process models in a virtual environment to construct a digital model that is completely consistent with the characteristics, behaviors, and performance of a real physical object. Through digital model simulation, the state of the real physical object can be predicted.

[0004] How to use digital twin technology to create static and dynamic simulation models including a gas equipment system and perform dynamic simulation during the design stage to verify and optimize the process flow, dynamic performance, and automation control program of the gas equipment system before the actual ship test has become a technical problem to be solved.

[0005] Therefore, providing a dynamic simulation method for a gas equipment system based on digital twin technology can solve the above problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is how to use digital twin technology to create static and dynamic simulation models including a gas equipment system and perform dynamic simulation during the design stage to verify and optimize the process flow, dynamic performance, and automation control program of the gas equipment system before the actual ship test. Therefore, a dynamic simulation method for a gas equipment system based on digital twin technology is provided. The dynamic simulation method for a gas equipment system based on digital twin technology includes:

[0007] Obtain the typical operating conditions of the gas equipment system, obtain the process design parameters of the system equipment components under the typical operating conditions of the gas equipment system, establish a static simulation model of the gas equipment system based on digital twin technology, and input the obtained process design parameters of the system equipment components into the static simulation model of the gas equipment system;

[0008] Establish a connection between the static simulation model of the gas equipment system and the signals of the database and the automation control program of the gas equipment system to create a dynamic simulation model of the gas equipment system;

[0009] Load the automation control program of the gas equipment system onto the virtual simulator, and perform real-time data exchange between the virtual simulator and the dynamic simulation model of the gas equipment system to form a closed-loop dynamic simulation platform;

[0010] Input the initial operating conditions of several typical operating conditions of the gas equipment system into the dynamic simulation model of the gas equipment system, and run the automation control program in the closed-loop dynamic simulation platform to generate the operating result parameter information of the gas equipment system corresponding to several typical operating conditions;

[0011] Generate adjustment strategy information based on the operating result parameter information of the typical operating conditions, substitute the adjustment strategy information into the dynamic simulation model of the gas equipment system, and obtain the optimal adjustment strategy of the gas equipment system;

[0012] Adjust the automation control program of the gas equipment system according to the optimal adjustment strategy.

[0013] Optionally, the gas equipment system includes a dual-fuel boiler, a first dual-fuel power generation engine, a second dual-fuel power generation engine, a third dual-fuel power generation engine, a high-pressure dual-fuel main propulsion engine, a first main gas valve, a second main gas valve, a third main gas valve, a low-temperature gas buffer tank, a pressure regulating valve, a gas compressor, a compressor bypass control valve, a low-pressure LNG evaporator, a high-pressure gas buffer tank, a high-pressure LNG evaporator, a high-pressure LNG reciprocating pump, a reciprocating pump bypass control valve, a low-pressure pump bypass control valve, an LNG storage tank, an LNG submersible pump, and an LNG deep well pump. The LNG deep well pump and the LNG submersible pump are arranged in the LNG storage tank. The LNG storage tank is connected to the gas compressor through a pipeline. The gas compressor is connected to the gas cooler. A bypass is arranged on the side of the gas compressor and the gas cooler, and a compressor bypass control valve is arranged on the bypass. One end of the pressure regulating valve is connected to the gas cooler, and the other end is connected to the low-pressure gas buffer tank. The low-pressure gas buffer tank is connected to the third main gas valve, and the third main gas valve is connected to the dual-fuel boiler. The LNG deep well pump is simultaneously connected to the low-pressure pump bypass control valve, the high-pressure LNG reciprocating pump, and the low-pressure LNG evaporator. The low-pressure LNG evaporator is connected to the low-pressure gas buffer tank. The low-pressure gas buffer tank is connected to the second main gas valve, and the second main gas valve is simultaneously connected to the first dual-fuel power generation engine, the second dual-fuel power generation engine, and the third dual-fuel power generation engine. The high-pressure LNG reciprocating pump is connected to the high-pressure LNG evaporator. A bypass is arranged on the side of the high-pressure LNG reciprocating pump, and a reciprocating pump bypass control valve is arranged on the bypass. One end of the high-pressure gas buffer tank is connected to the high-pressure LNG evaporator, and the other end is connected to the first main gas valve. The first main gas valve is connected to the high-pressure dual-fuel main propulsion engine.

[0014] Optionally, the typical operating conditions include:

[0015] The first typical operating condition: the stable operating condition of high-pressure gas at the maximum flow rate and the instantaneous switching from the stable operating condition of high-pressure gas at the maximum flow rate to the emergency gas cut-off condition;

[0016] The second typical operating condition: the stable operating condition of low-pressure gas at the maximum flow rate and the instantaneous switching from the stable operating condition of low-pressure gas at the maximum flow rate to the emergency gas cut-off condition;

[0017] The third typical operating condition: the stable operating condition of simultaneous supply of high-pressure and low-pressure gas at the maximum flow rate and the instantaneous switching from the stable operating condition of simultaneous supply of high-pressure and low-pressure gas at the maximum flow rate to the emergency gas cut-off condition;

[0018] Fourth typical operating condition: The stable operation of the high-pressure and low-pressure gas supply at the maximum flow rate is switched to the stable operation of the high-pressure and low-pressure gas supply at the minimum flow rate;

[0019] The specific process of the first typical operating condition includes:

[0020] Start the LNG deep well pump or submersible pump, use the LNG transported by the LNG deep well pump or submersible pump to precool the high-pressure LNG reciprocating pump. When the temperature of the high-pressure LNG reciprocating pump is precooled to below -130°C, start the high-pressure LNG reciprocating pump. The high-pressure dual-fuel main propulsion engine switches to gas operation, the main gas valve of the high-pressure dual-fuel main propulsion engine opens, the load of the high-pressure dual-fuel main propulsion engine is loaded to 100% load, and the high-pressure gas operates stably at the maximum flow rate; then, due to a fault, the gas supply of the high-pressure dual-fuel main propulsion engine is instantaneously cut off, and it switches to fuel mode operation;

[0021] The specific process of the second typical operating condition includes:

[0022] Start the LNG deep well pump or submersible pump, start the gas compressor, and the 3 low-pressure dual-fuel power generation engines and 1 low-pressure dual-fuel boiler are switched from fuel mode to gas operation one by one. The main gas valves of the power generation engines and the boiler open. The loads of the 3 power generation engines are all adjusted to 70% load, and the load of 1 boiler is adjusted to 100% load. The low-pressure gas operates stably at the maximum flow rate; then, due to a fault, the gas supply of the 3 power generation engines and 1 boiler is instantaneously cut off at the same time. The 3 power generation engines switch to fuel mode operation, and 1 boiler stops operating;

[0023] The specific process of the third typical operating condition includes:

[0024] Start the LNG deep well pump or submersible pump, start the gas compressor, and the 2 low-pressure dual-fuel power generation engines and 1 low-pressure dual-fuel boiler are switched from fuel mode to gas operation one by one. The main gas valves of the power generation engines and the boiler open. The gas operation loads of the 2 power generation engines are all adjusted to 55% load, and the gas operation load of 1 boiler is adjusted to 45% load. Use the LNG transported by the LNG deep well pump or submersible pump to precool the high-pressure LNG reciprocating pump. When the temperature of the high-pressure LNG reciprocating pump is precooled to below -130°C, start the high-pressure LNG reciprocating pump. The high-pressure dual-fuel main propulsion engine switches from fuel mode to gas operation, the main gas valve of the high-pressure dual-fuel main propulsion engine opens, and the load of the high-pressure dual-fuel main propulsion engine is loaded to 100% load. At this time, the high-pressure and low-pressure gas supply operates stably at the maximum flow rate; then, due to a fault, the gas supply of the high-pressure dual-fuel main propulsion engine, 2 power generation engines, and 1 boiler is instantaneously cut off at the same time. The high-pressure dual-fuel main propulsion engine and 2 power generation engines switch to fuel mode operation, and 1 boiler stops operating;

[0025] The specific process of the fourth typical operating condition includes:

[0026] Start the LNG deep well pump or submersible pump, start the gas compressor, and gradually switch 2 low-pressure dual-fuel power generation engines and 1 low-pressure dual-fuel boiler from the fuel mode to gas operation. Open the main gas valves of the power generation engines and the main gas valve of the boiler. Adjust the gas operation load of the 2 power generation engines to 55% load, and adjust the gas operation load of 1 boiler to 45% load. Use the LNG transported by the LNG deep well pump or submersible pump to pre-cool the high-pressure LNG reciprocating pump. When the temperature of the high-pressure LNG reciprocating pump is pre-cooled to below -130°C, start the high-pressure LNG reciprocating pump. Switch the high-pressure dual-fuel main propulsion engine from the fuel mode to gas operation, open the main gas valve of the high-pressure dual-fuel main propulsion engine, and load the high-pressure dual-fuel main propulsion engine to 100% load. At this time, high-pressure and low-pressure gas are supplied simultaneously and operate stably at the maximum flow rate; furthermore, 1 power generation engine and 1 boiler are simultaneously cut off from gas due to a fault. This power generation engine switches to fuel mode operation, and this boiler stops operating. Adjust the gas operation load of the high-pressure dual-fuel main propulsion engine to 10% load, and adjust the gas operation load of the other power generation engine to 40%. At this time, high-pressure and low-pressure gas are supplied simultaneously and operate stably at the minimum flow rate.

[0027] Optionally, the establishment of the static simulation model of the gas equipment system based on digital twin technology includes:

[0028] Obtain the process design parameters of each equipment component in the gas equipment system respectively, and construct the physical relationship sub-models of the gas equipment system and each equipment component. The physical relationship sub-models include: the physical relationship sub-model of the pressure and temperature of the LNG storage tank; the physical relationship sub-model of the flow rate and head of the LNG deep well pump or submersible pump; the physical relationship sub-model of the flow rate, exhaust pressure and temperature of the gas compressor; the physical relationship sub-model of the flow rate and head of the high-pressure LNG reciprocating pump; the physical relationship sub-model of the two-phase flow conversion of the liquid and gas phases of the low-pressure LNG evaporator; the physical relationship sub-model of the two-phase flow conversion of the liquid and gas phases of the high-pressure LNG evaporator; the physical relationship sub-model of the gas heat exchange of the gas cooler; the physical relationship sub-model of the flow rate and pressure loss of the LNG liquid and gas pipelines; the physical relationship sub-model of the load setting of the gas-using equipment.

[0029] Based on the physical relationship sub-models of the gas equipment system and each equipment component, construct the multi-physical quantity static simulation sub-models of each component corresponding to the physical relationship sub-models one by one;

[0030] According to the physical process flow and numerical calculation relationship among the system equipment components of the gas equipment system, the static simulation sub-models of the system equipment components of the gas equipment system are connected to create a complete static simulation model of the gas equipment system.

[0031] Optionally, the initial operating conditions are the initial set values for the operation of the dynamic simulation model of the gas equipment system, including the initial liquid level height, initial pressure, initial temperature, external ambient temperature, composition of LNG, composition ratio of the heat exchange medium water glycol in the LNG evaporator, the initial states of the gas equipment system and the gas-using equipment, and the load setting of the gas-using equipment.

[0032] Optionally, generating the adjustment strategy information according to the operation result parameter information of the typical operating conditions includes:

[0033] Based on the dynamic simulation model of the gas equipment system, according to the workflow of a certain operating condition among the selected typical operating conditions, input the initial operating conditions into the dynamic simulation model of the gas equipment system, run the automation control program of the gas equipment system through the PLC virtual simulator, and perform real-time data exchange with the dynamic simulation model of the gas equipment system to update the dynamic simulation model of the gas equipment system and obtain the current operation result parameters of the dynamic simulation model of the gas equipment system under the current operating condition.

[0034] Compare the current operation result parameters with the process design parameters of the same operating condition to obtain the current difference value of the current operating condition. If the current difference value does not meet the design limit value, analyze and obtain the adjustment strategy of the automation control program of the gas equipment system under the current operating condition.

[0035] Based on the operation result parameters of the dynamic simulation models of different typical operating conditions, analyze and generate multiple adjustment strategies for the automation control program of the gas equipment system.

[0036] Optionally, the operation result parameters of the dynamic simulation model of the gas equipment system include the operation result parameters of the pressure and temperature of the gas supply from the gas equipment system to the gas-using equipment changing with time; from the operation result parameters of the pressure and temperature changing with time, obtain the steady-state values and instantaneous change values of the gas supply pressure and temperature.

[0037] Optionally, the optimal adjustment strategy of the automation control program of the gas equipment system includes performing a linear programming algorithm of the simplex method based on the multiple adjustment strategies, and through calculation iteration until the optimal adjustment strategy of the automation control program is found.

[0038] Optionally, the closed-loop dynamic simulation platform includes loading the automation control program of the gas equipment system into a PLC virtual simulator, simulating a PLC controller through the PLC virtual simulator to run the automation control program of the gas equipment system, and performing real-time data exchange with the dynamic simulation model of the gas equipment system to form a closed-loop dynamic simulation platform;

[0039] The closed-loop dynamic simulation platform is used to simulate the dynamic changes in the temperature and pressure of liquid-phase and gas-phase LNG occurring in the gas equipment system over time.

[0040] Optionally, the establishment process of the dynamic simulation model of the gas equipment system specifically includes:

[0041] Establishing connections of signals and databases between the static simulation model of the gas equipment system and the automation control program of the gas equipment system;

[0042] Inputting the input signals and data required by the automation control program of the gas equipment system into the static simulation model of the gas equipment system; or, outputting the output signals and data required by the automation control program of the gas equipment system from the static simulation model of the gas equipment system;

[0043] Forming a dynamic simulation model of the gas equipment system;

[0044] The specific process of establishing connections of signals and databases between the static simulation model of the gas equipment system and the automation control program of the gas equipment system includes:

[0045] Configuring the input and output signals of the static simulation model of the gas equipment system according to the interface information of the automation control program of the gas equipment system;

[0046] Adding the output signal of the automation control program of the gas equipment system as an input signal to the static simulation model of the gas equipment system into the static simulation model of the gas equipment system;

[0047] Similarly, the input signals required by the automation control program of the gas equipment system are the signal outputs calculated from the static simulation model of the gas equipment system. It is necessary to extract them from the static simulation model of the gas equipment system according to the positions and feedback information of the sensors in the actual gas equipment system and feed them back to the automation control program of the gas equipment system as input signals.

[0048] Optionally, input the process design parameters of the system equipment components that have been collected into the static simulation model to simulate the flow rate, temperature, and pressure conditions of the gas equipment system for liquid-phase and gas-phase LNG under a certain specific system state. This includes inputting the process design parameters of the system equipment components of the gas equipment system under various typical operating conditions into the static simulation sub-models of each system equipment component, including: inputting parameters such as the LNG storage tank size, volume, cold insulation area, LNG tank pressure, and natural evaporation rate of LNG in the tank under different initial filling rates into the sub-model of LNG storage tank pressure and temperature; inputting parameters such as the impeller size of the pump, flow rate, pressure, and mechanical efficiency at different rotational speeds into the sub-model of LNG deep well pump or submersible pump flow rate and pressure; inputting parameters such as the suction pressure, suction superheat temperature, discharge pressure, discharge temperature, mass flow rate, power, volumetric efficiency, and isentropic efficiency at different rotational speeds into the sub-model of gas compressor flow rate, discharge pressure, and temperature; inputting parameters such as the piston size of the pump, volumetric flow rate and pressure at different rotational speeds into the sub-model of high-pressure LNG reciprocating pump flow rate and pressure; inputting parameters such as the hot-side fluid inlet temperature and volumetric flow rate, cold-side fluid inlet temperature and volumetric flow rate, heat exchange power, specific heat of the heat transfer medium, and pressure loss on the gas side of the low-pressure LNG evaporator into the sub-model of the two-phase flow conversion of liquid-phase and gas-phase in the low-pressure LNG evaporator; inputting parameters such as the hot-side fluid inlet temperature and volumetric flow rate, cold-side fluid inlet temperature and volumetric flow rate, heat exchange power, specific heat of the heat transfer medium, and pressure loss on the gas side of the high-pressure LNG evaporator into the sub-model of the two-phase flow conversion of liquid-phase and gas-phase in the high-pressure LNG evaporator; inputting parameters such as the hot-side fluid inlet temperature and volumetric flow rate, cold-side fluid inlet temperature and volumetric flow rate, heat exchange power, specific heat of the heat transfer medium, and pressure loss on the gas side of the gas cooler into the sub-model of the physical relationship of gas heat exchange in the gas cooler; inputting parameters such as the inner diameter and length dimensions of each liquid-phase and gas-phase pipeline of LNG into the sub-model of LNG liquid-phase and gas-phase pipeline flow rate and pressure loss; inputting the interaction signal parameters for gas switching and operation between the gas equipment system and the gas-using equipment into the sub-model of gas switching and operation signal interaction of the gas-using equipment to simulate the switching of the gas-using equipment from the fuel mode to the gas mode and operation; inputting the parameters of the gas pressure, temperature, flow rate values, and their fluctuation limit values required by the gas-using equipment under different gas consumption loads into the sub-model of gas consumption load setting of the gas-using equipment.

[0049] Implementing the present invention has the following beneficial effects:

[0050] Generally, the entire gas equipment system on a real ship must be installed before the whole gas equipment system can be tested. If problems are found, rework and adjustment are required. This patent uses digital twin technology to create static and dynamic simulation models of the gas equipment system and conduct dynamic simulations to verify and optimize the technological process, dynamic performance, and automation control program of the gas equipment system in advance before the real ship test. It has guiding significance for the design and development of the gas equipment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a schematic flowchart of a dynamic simulation method for a gas equipment system based on digital twin technology proposed in an embodiment of the present application;

[0052] Figure 2 is a simple schematic diagram of the gas equipment system proposed in an embodiment of the present application;

[0053] Figure 3 is a schematic structural diagram of a closed-loop dynamic simulation platform proposed in an embodiment of the present application;

[0054] Figure 4 is a schematic diagram of a set of gas pressure operation result parameters of a dynamic simulation model proposed in an embodiment of the present application;

[0055] Figure 5 is a schematic diagram of the physical relationship between the flow rate and head of an LNG deep well pump in a multi-physical quantity static model proposed in an embodiment of the present application.

[0056] Figure 6 is a schematic diagram of the physical relationship between the flow rate, discharge pressure, and temperature of a gas compressor in a multi-physical quantity static model proposed in an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0058] Embodiment

[0059] Please refer to the attached drawings of the specification. The technical problem to be solved in this embodiment is how to create static and dynamic simulation models including the gas equipment system using digital twin technology during the design stage, and conduct dynamic simulation to verify and optimize the process flow, dynamic performance, and automation control program of the gas equipment system in advance before the actual ship test. Therefore, a dynamic simulation of the gas equipment system based on digital twin technology is provided. The dynamic simulation of the gas equipment system based on digital twin technology includes:

[0060] Step 1: Obtain the typical operating conditions of the gas equipment system, obtain the process design parameters of the system equipment components in the typical operating conditions of the gas equipment system, establish a static simulation model of the gas equipment system based on digital twin technology, and input the obtained process design parameters of the system equipment components into the static simulation model of the gas equipment system.

[0061] Among them, the execution entity of the dynamic simulation method of the gas equipment system based on digital twin technology in this embodiment can be, but is not limited to, the dynamic simulation device of the gas equipment system based on digital twin technology. This device is implemented in software and hardware, and can include, but is not limited to, the client side, the server side, etc.

[0062] Among them, the gas equipment system refers to the equipment system used to provide gas with suitable pressure, temperature, and flow required by gas-using equipment. Figure 2Shown is a simple schematic diagram of a gas equipment system proposed in an embodiment of the present application. The gas equipment system includes a dual-fuel boiler, a first dual-fuel power generation engine, a second dual-fuel power generation engine, a third dual-fuel power generation engine, a high-pressure dual-fuel main propulsion engine, a first main gas valve, a second main gas valve, a third main gas valve, a low-temperature gas buffer tank, a pressure regulating valve, a gas compressor, a compressor bypass control valve, a low-pressure LNG evaporator, a high-pressure gas buffer tank, a high-pressure LNG evaporator, a high-pressure LNG reciprocating pump, a reciprocating pump bypass control valve, a low-pressure pump bypass control valve, an LNG storage tank, an LNG submersible pump, and an LNG deep well pump. The LNG deep well pump and the LNG submersible pump are arranged in the LNG storage tank. The LNG storage tank is connected to the gas compressor through a pipeline. The gas compressor is connected to the gas cooler. A bypass is provided on the side of the gas compressor and the gas cooler, and a compressor bypass control valve is arranged on the bypass. One end of the pressure regulating valve is connected to the gas cooler, and the other end of the pressure regulating valve is connected to the low-pressure gas buffer tank. The low-pressure gas buffer tank is connected to the third main gas valve, and the third main gas valve is connected to the dual-fuel boiler. The LNG deep well pump is simultaneously connected to the low-pressure pump bypass control valve, the high-pressure LNG reciprocating pump, and the low-pressure LNG evaporator. The low-pressure LNG evaporator is connected to the low-pressure gas buffer tank. The low-pressure gas buffer tank is connected to the second main gas valve, and the second main gas valve is simultaneously connected to the first dual-fuel power generation engine, the second dual-fuel power generation engine, and the third dual-fuel power generation engine. The high-pressure LNG reciprocating pump is connected to the high-pressure LNG evaporator. A bypass is provided on the side of the high-pressure LNG reciprocating pump, and a reciprocating pump bypass control valve is arranged on the bypass. One end of the high-pressure gas buffer tank is connected to the high-pressure LNG evaporator, and the other end of the high-pressure gas buffer tank is connected to the first main gas valve. The first main gas valve is connected to the high-pressure dual-fuel main propulsion engine.

[0063] Among them, the typical operating conditions of the gas equipment system include:

[0064] The first typical operating condition: the stable operating condition of high-pressure gas at the maximum flow rate and the instantaneous switching from the stable operating condition of high-pressure gas at the maximum flow rate to the emergency gas cut-off condition;

[0065] The second typical operating condition: the stable operating condition of low-pressure gas at the maximum flow rate and the instantaneous switching from the stable operating condition of low-pressure gas at the maximum flow rate to the emergency gas cut-off condition;

[0066] The third typical operating condition: the stable operating condition of high-pressure and low-pressure gases simultaneously supplied at the maximum flow rate and the instantaneous switching from the stable operating condition of high-pressure and low-pressure gases simultaneously supplied at the maximum flow rate to the emergency gas cut-off condition;

[0067] The fourth typical operating condition: the stable operation of the simultaneous supply of high-pressure and low-pressure gas at the maximum flow rate is switched to the stable operation of the simultaneous supply of high-pressure and low-pressure gas at the minimum flow rate;

[0068] The specific process of the first typical operating condition includes:

[0069] Start the LNG deep well pump or submersible pump, and use the LNG transported by the LNG deep well pump or submersible pump to pre-cool the high-pressure LNG reciprocating pump. When the temperature of the high-pressure LNG reciprocating pump is pre-cooled to below -130°C, start the high-pressure LNG reciprocating pump. The high-pressure dual-fuel main propulsion engine switches to gas operation, the main gas valve of the high-pressure dual-fuel main propulsion engine opens, the load of the high-pressure dual-fuel main propulsion engine is loaded to 100% load, and the high-pressure gas operates stably at the maximum flow rate; then, due to a momentary gas cut-off of the high-pressure dual-fuel main propulsion engine due to a fault, it switches to fuel mode operation;

[0070] The specific process of the second typical operating condition includes:

[0071] Start the LNG deep well pump or submersible pump, start the gas compressor, and the 3 low-pressure dual-fuel power generation engines and 1 low-pressure dual-fuel boiler are successively switched from fuel mode to gas operation. The main gas valves of the power generation engines and the main gas valve of the boiler open. The loads of the 3 power generation engines are all adjusted to 70% load, and the load of 1 boiler is adjusted to 100% load. The low-pressure gas operates stably at the maximum flow rate; then, due to a momentary simultaneous gas cut-off of the 3 power generation engines and 1 boiler due to a fault, the 3 power generation engines switch to fuel mode operation, and 1 boiler stops operating;

[0072] The specific process of the third typical operating condition includes:

[0073] Start the LNG deep well pump or submersible pump, start the gas compressor, and gradually switch the 2 low-pressure dual-fuel power generation engines and 1 low-pressure dual-fuel boiler from the fuel mode to gas operation. Open the main gas valves of the power generation engines and the main gas valve of the boiler. Adjust the gas operation load of the 2 power generation engines to 55% load, and adjust the gas operation load of 1 boiler to 45% load. Use the LNG transported by the LNG deep well pump or submersible pump to pre-cool the high-pressure LNG reciprocating pump. When the temperature of the high-pressure LNG reciprocating pump is pre-cooled to below -130 °C, start the high-pressure LNG reciprocating pump. Switch the high-pressure dual-fuel main propulsion engine from the fuel mode to gas operation, open the main gas valve of the high-pressure dual-fuel main propulsion engine, and load the high-pressure dual-fuel main propulsion engine to 100% load. At this time, the high-pressure and low-pressure gas supply simultaneously operates stably at the maximum flow rate; furthermore, the high-pressure dual-fuel main propulsion engine, 2 power generation engines, and 1 boiler are simultaneously cut off from the gas supply due to a fault. The high-pressure dual-fuel main propulsion engine and 2 power generation engines are switched to the fuel mode for operation, and 1 boiler stops operating;

[0074] The specific process of the fourth typical operating condition includes:

[0075] Start the LNG deep well pump or submersible pump, start the gas compressor, and gradually switch the 2 low-pressure dual-fuel power generation engines and 1 low-pressure dual-fuel boiler from the fuel mode to gas operation. Open the main gas valves of the power generation engines and the main gas valve of the boiler. Adjust the gas operation load of the 2 power generation engines to 55% load, and adjust the gas operation load of 1 boiler to 45% load. Use the LNG transported by the LNG deep well pump or submersible pump to pre-cool the high-pressure LNG reciprocating pump. When the temperature of the high-pressure LNG reciprocating pump is pre-cooled to below -130 °C, start the high-pressure LNG reciprocating pump. Switch the high-pressure dual-fuel main propulsion engine from the fuel mode to gas operation, open the main gas valve of the high-pressure dual-fuel main propulsion engine, and load the high-pressure dual-fuel main propulsion engine to 100% load. At this time, the high-pressure and low-pressure gas supply simultaneously operates stably at the maximum flow rate; furthermore, 1 power generation engine and 1 boiler are simultaneously cut off from the gas supply due to a fault. This power generation engine is switched to the fuel mode for operation, and this boiler stops operating. Adjust the gas operation load of the high-pressure dual-fuel main propulsion engine to 10% load, and adjust the gas operation load of the other power generation engine to 40%. At this time, the high-pressure and low-pressure gas supply simultaneously operates stably at the minimum flow rate.

[0076] Among them, the static simulation model of the gas equipment system based on digital twin technology includes the following establishment steps:

[0077] According to the operating principles and process design parameters of the system equipment components of the gas equipment system, construct a physical relationship sub-model of the system equipment components of the gas equipment system;

[0078] Based on the physical relationship sub-model of the system equipment components of the gas equipment system, using tools such as principle, mechanism or process models in digital simulation software, construct multiple multi-physical quantity static simulation sub-models that can accurately reflect the states of the system equipment components in the gas equipment system;

[0079] According to the physical process flow and numerical calculation relationship among the system equipment components of the gas equipment system, connect the static simulation sub-models of the system equipment components of the gas equipment system to create a complete static simulation model of the gas equipment system.

[0080] Among them, the static simulation sub-model of the gas equipment system based on digital twin technology reflects the characteristics, motion and performance of the system equipment components in the gas equipment system under a specific system state, without considering the influence of time passage on the state. The multiple created multi-physical quantity static simulation sub-models include: the physical relationship sub-model of the pressure and temperature of the LNG storage tank; the physical relationship sub-model of the flow rate and head of the LNG deep well pump or submersible pump; the physical relationship sub-model of the flow rate, discharge pressure and temperature of the gas compressor; the physical relationship sub-model of the flow rate and head of the high-pressure LNG reciprocating pump; the physical relationship sub-model of the liquid-gas two-phase flow conversion of the low-pressure LNG evaporator; the physical relationship sub-model of the liquid-gas two-phase flow conversion of the high-pressure LNG evaporator; the physical relationship sub-model of the gas heat exchange of the gas cooler; the physical relationship sub-model of the flow rate and pressure loss of the LNG liquid and gas pipelines; the physical relationship sub-model of the load setting of the gas using equipment.

[0081] Among them, Figure 5 is a schematic diagram of the physical relationship between the flow rate and head of the LNG deep well pump in the multi-physical quantity static model. The physical relationship sub-model of the flow rate and head of the LNG deep well pump includes the establishment of the physical relationship between the flow rate and head.

[0082] Figure 6 is a schematic diagram of the physical relationship between the flow rate, discharge pressure and temperature of the gas compressor in the multi-physical quantity static model. The physical relationship sub-model of the flow rate, discharge pressure and temperature of the gas compressor includes the establishment of the physical relationship between the flow rate, discharge pressure and temperature of the gas compressor.

[0083] Among them, the process design parameters of the collected system equipment components are input into the model, that is, the process design parameters of the system equipment components of the gas equipment system under various typical operating conditions are input into the static simulation sub-models of each system equipment component, which are used to simulate the temperature and pressure conditions of the gas equipment system for liquid-phase and gas-phase LNG under a certain specific system state, including: inputting parameters such as the LNG storage tank size, volume, cold insulation area, LNG tank pressure and natural evaporation rate of LNG in the tank under different initial filling rates into the sub-model of the LNG storage tank pressure and temperature; inputting parameters such as the impeller size of the pump, flow rate, pressure, mechanical efficiency, etc. at different rotational speeds into the sub-model of the LNG deep well pump or submersible pump flow rate and pressure; inputting parameters such as the suction pressure, suction superheat degree, discharge pressure, discharge temperature, mass flow rate, power, volumetric efficiency, isentropic efficiency, etc. at different rotational speeds into the sub-model of the gas compressor flow rate, discharge pressure and temperature; inputting the piston size of the pump, volume flow rate and pressure at different rotational speeds into the sub-model of the high-pressure LNG reciprocating pump flow rate and pressure; inputting parameters such as the hot-side fluid inlet temperature and volume flow rate, cold-side fluid inlet temperature and volume flow rate, heat exchange power, specific heat of the heat transfer medium, pressure loss on the gas side, etc. of the low-pressure LNG evaporator into the sub-model of the liquid-phase and gas-phase two-phase flow conversion of the low-pressure LNG evaporator; inputting parameters such as the hot-side fluid inlet temperature and volume flow rate, cold-side fluid inlet temperature and volume flow rate, heat exchange power, specific heat of the heat transfer medium, pressure loss on the gas side, etc. of the high-pressure LNG evaporator into the sub-model of the liquid-phase and gas-phase two-phase flow conversion of the high-pressure LNG evaporator; inputting parameters such as the hot-side fluid inlet temperature and volume flow rate, cold-side fluid inlet temperature and volume flow rate, heat exchange power, specific heat of the heat transfer medium, pressure loss on the gas side, etc. of the gas cooler into the sub-model of the physical relationship of the gas heat exchange of the gas cooler; inputting parameters such as the inner diameter and length dimensions of each LNG liquid-phase and gas-phase pipeline into the sub-model of the LNG liquid-phase and gas-phase pipeline flow rate and pressure loss; inputting the interaction signal parameters for gas switching and operation between the gas equipment system and the gas-using equipment into the sub-model of the gas switching and operation signal interaction of the gas-using equipment, which is used to simulate the switching of the gas-using equipment from the fuel mode to the gas mode and operation; inputting parameters such as the gas pressure, temperature, flow rate values required by the gas-using equipment under different gas consumption loads and their fluctuation limit values into the sub-model of the gas-using equipment load setting.

[0084] Step 2: Establish a connection between the static simulation model of the gas equipment system, the database of the gas equipment system, and the signals of the automation control program to create a dynamic simulation model of the gas equipment system.

[0085] Among them, by connecting signals and databases between the static simulation model of the gas equipment system and the automation control program of the gas equipment system, the output or input signals and data required by the automation control program of the gas equipment system are input or output in the static simulation model of the gas equipment system, forming a dynamic simulation model of the gas equipment system.

[0086] Among them, establishing the connection of signals and databases between the static simulation model of the gas equipment system and the automation control program of the gas equipment system includes configuring the input and output signals of the static simulation model of the gas equipment system according to the interface information of the automation control program of the gas equipment system, and adding the output signal of the automation control program of the gas equipment system as the input signal of the static simulation model of the gas equipment system to the static simulation model of the gas equipment system; similarly, the input signal required by the automation control program of the gas equipment system is the signal output calculated by the static simulation model of the gas equipment system, and it needs to be extracted from the static simulation model of the gas equipment system and fed back to the automation control program of the gas equipment system as the input signal according to the position and feedback information of the sensors in the actual gas equipment system.

[0087] Step 3: Load the automation control program of the gas equipment system onto the virtual simulator, and perform real-time data exchange between the virtual simulator and the dynamic simulation model of the gas equipment system to form a closed-loop dynamic simulation platform for simulating the dynamic changes in the temperature and pressure of liquid-phase and gas-phase LNG occurring in the gas equipment system over time.

[0088] Among them, the PLC virtual simulator is a software that can create a virtual PLC controller. The automation control program for running the gas equipment system in this application can be, but is not limited to, running the automation program of the gas equipment system through the PLC virtual simulator, or a PLC entity can be used to replace the PLC virtual simulator to implement the operation of the automation control program of the gas equipment system.

[0089] Among them, as Figure 3 shown is the structural schematic diagram of the closed-loop dynamic simulation platform.

[0090] Step 4: Based on the closed-loop dynamic simulation platform, input the initial operating conditions of several typical operating conditions of the gas equipment system into the dynamic simulation model of the gas equipment system, and run the automation control program in the simulation dynamic model to generate the operating result parameter information of the gas equipment system corresponding to several typical operating conditions.

[0091] Among them, the initial operating conditions are the initial set values for the operation of the dynamic simulation model of the gas equipment system, including the initial liquid level height, initial pressure, and initial temperature of the LNG storage tank, the external environmental temperature, the composition of the LNG, the composition ratio of the heat exchange medium water glycol in the LNG evaporator, the initial states of the gas equipment system and the gas-using equipment, the load setting of the gas-using equipment, etc. The initial states of the gas equipment system and the gas-using equipment, and the load setting of the gas-using equipment change with the operating conditions. The composition of the LNG is determined by the quality of the LNG filled.

[0092] Among them, the operation result parameters of the dynamic simulation model of the gas equipment system include the operation result parameters of the pressure and temperature of the gas supply from the gas equipment system to the gas-using equipment changing with time. From the operation result parameters of the pressure and temperature changing with time, the steady-state values and instantaneous change values of the gas supply pressure and temperature are obtained.

[0093] Among them, the gas-using equipment includes high-pressure dual-fuel main propulsion engines, low-pressure dual-fuel power generation engines, and low-pressure dual-fuel boilers. These gas-using equipment can use fuel oil as fuel or gas as fuel. The number of gas-using equipment includes but is not limited to Figure 2 the number of equipment shown.

[0094] Step 5: Generate adjustment strategy information according to the operation result parameter information of the typical operating conditions, substitute the adjustment strategy information into the dynamic simulation model of the gas equipment system, and obtain the optimal adjustment strategy of the gas equipment system.

[0095] Among them, the multiple adjustment strategies of the automatic control program of the gas equipment system include:

[0096] Based on the dynamic simulation model of the gas equipment system, according to the working process of a certain operating condition in the selected typical operating conditions, input the initial operating conditions into the dynamic simulation model of the gas equipment system, run the automatic control program of the gas equipment system through the PLC virtual simulator, and perform real-time data exchange with the dynamic simulation model of the gas equipment system to update the dynamic simulation model of the gas equipment system and obtain the current operation result parameters of the dynamic simulation model of the gas equipment system under the current operating conditions. Compare the current operation result parameters with the process design parameters of the same operating conditions to obtain the current difference value of the current operating conditions. If the current difference value does not meet the design limit value, analyze and obtain the adjustment strategy of the automatic control program of the gas equipment system under the current operating conditions so that the difference value meets the design limit value.

[0097] Based on the operation result parameters of the dynamic simulation models of the different typical operating conditions, analyze and obtain multiple adjustment strategies of the automatic control program of the gas equipment system.

[0098] Among them, as Figure 4 shown is a schematic diagram of a set of gas pressure operation result parameters of the dynamic simulation model of the gas equipment system. Figure 4 In the schematic diagram of the first gas pressure operation result parameter, there is a problem of insufficient gas pressure. In the schematic diagram of the second gas pressure operation result parameter, there is a problem of large gas pressure fluctuation. The schematic diagram of the third gas pressure operation result parameter shows that the gas pressure is relatively stable.

[0099] Among them, the adjustment strategy of the automatic control program of the gas equipment system under the current operating condition involves one adjustment or a combination of multiple adjustments of the associated control strategy of the gas supply pressure and temperature output by the gas equipment system, including the frequency conversion control strategy of the LNG deep well pump or submersible pump motor, the bypass control valve control strategy of the LNG deep well pump or submersible pump, the frequency conversion control strategy of the gas compressor motor, the bypass control valve control strategy of the gas compressor, the frequency conversion control strategy of the high-pressure LNG reciprocating pump motor, the bypass control valve control strategy of the high-pressure LNG reciprocating pump, the pressure regulating valve control strategy of the low-pressure buffer tank, and the control strategy of the heating or cooling medium ethylene glycol water temperature control valve of the LNG evaporator.

[0100] Among them, the associated control strategy includes, but is not limited to, the PID control strategy. The adjustment of the associated control strategy includes the adjustment of the associated control parameters of the associated control strategy. If the PID control strategy is adopted for the associated control strategy, it includes the adjustment of the proportional, derivative, and integral associated control parameters of the PID control strategy.

[0101] Adjust the automatic control program of the gas equipment system according to the optimal adjustment strategy.

[0102] Among them, based on the multiple adjustment strategies, calculate and iterate through the linear programming algorithm until the optimal adjustment strategy of the automatic control program is found.

[0103] Step 6: Adjust the automatic control program of the gas equipment system based on the optimal adjustment strategy of the automatic control program of the gas equipment system.

[0104] Among them, the adjustment of the automatic control program includes the adjustment of the associated control parameters of the associated control strategy.

[0105] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A dynamic simulation method for a gas equipment system based on digital twin technology, characterized in that, Including: Obtain the typical operating conditions of the gas equipment system, obtain the process design parameters of the system equipment components in the typical operating conditions of the gas equipment system, establish a static simulation model of the gas equipment system based on digital twin technology, and input the obtained process design parameters of the system equipment components into the static simulation model of the gas equipment system; Establish a connection between the static simulation model of the gas equipment system and the signals of the database and the automation control program of the gas equipment system to create a dynamic simulation model of the gas equipment system; Load the automation control program of the gas equipment system onto the virtual simulator, and perform real-time data exchange between the virtual simulator and the dynamic simulation model of the gas equipment system to form a closed-loop dynamic simulation platform; Input the initial operating conditions of several typical operating conditions of the gas equipment system into the dynamic simulation model of the gas equipment system, and run the automation control program in the closed-loop dynamic simulation platform to generate the operating result parameter information of the gas equipment system corresponding to several typical operating conditions; Generate adjustment strategy information according to the operating result parameter information of the typical operating conditions, substitute the adjustment strategy information into the dynamic simulation model of the gas equipment system, and obtain the optimal adjustment strategy of the gas equipment system; Adjust the automation control program of the gas equipment system according to the optimal adjustment strategy; The establishment of the static simulation model of the gas equipment system based on digital twin technology includes: Respectively obtain the process design parameters of each equipment component in the gas equipment system, and construct a physical relationship sub-model of the gas equipment system and each equipment component. The physical relationship sub-model includes: a physical relationship sub-model of the pressure and temperature of the LNG storage tank; a physical relationship sub-model of the flow rate and head of the LNG deep well pump or submersible pump; a physical relationship sub-model of the flow rate, discharge pressure and temperature of the gas compressor; a physical relationship sub-model of the flow rate and head of the high-pressure LNG reciprocating pump; a physical relationship sub-model of the liquid-phase and gas-phase two-phase flow conversion of the low-pressure LNG evaporator; a physical relationship sub-model of the liquid-phase and gas-phase two-phase flow conversion of the high-pressure LNG evaporator; a physical relationship sub-model of the gas heat exchange of the gas cooler; a physical relationship sub-model of the flow rate and pressure loss of the LNG liquid-phase and gas-phase pipelines; a physical relationship sub-model of the load setting of the gas-using equipment; Based on the physical relationship sub-model of the gas equipment system and each equipment component, construct multi-physical quantity static simulation sub-models for each component corresponding to the physical relationship sub-model; According to the physical process flow and numerical calculation relationship between the system equipment components of the gas equipment system, connect the static simulation sub-models of the system equipment components of the gas equipment system to create a complete static simulation model of the gas equipment system; The establishment process of the dynamic simulation model of the gas equipment system specifically includes: Establish a connection of signals and databases between the static simulation model of the gas equipment system and the automation control program of the gas equipment system; Input the input signals and data required by the automation control program of the gas equipment system into the static simulation model of the gas equipment system; or, output the output signals and data required by the automation control program of the gas equipment system from the static simulation model of the gas equipment system; Form a dynamic simulation model of the gas equipment system; The specific process of establishing the connection of signals and databases between the static simulation model of the gas equipment system and the automation control program of the gas equipment system includes: Configure the input and output signals of the static simulation model of the gas equipment system according to the interface information of the automation control program of the gas equipment system; Add the output signal of the automation control program of the gas equipment system as the input signal of the static simulation model of the gas equipment system to the static simulation model of the gas equipment system; Similarly, the input signal required by the automation control program of the gas equipment system is from the signal output calculated by the static simulation model of the gas equipment system, and it needs to be extracted from the static simulation model of the gas equipment system and fed back to the automation control program of the gas equipment system as the input signal according to the position and feedback information of the sensors in the actual gas equipment system.

2. The dynamic simulation method of the gas equipment system based on the digital twin technology according to claim 1, characterized in that The gas equipment system includes a dual-fuel boiler, a first dual-fuel power generation engine, a second dual-fuel power generation engine, a third dual-fuel power generation engine, a high-pressure dual-fuel main propulsion engine, a first main gas valve, a second main gas valve, a third main gas valve, a low-pressure gas buffer tank, a pressure regulating valve, a gas cooler, a gas compressor, a compressor bypass control valve, a low-pressure LNG evaporator, a high-pressure gas buffer tank, a high-pressure LNG evaporator, a high-pressure LNG reciprocating pump, a reciprocating pump bypass control valve, a low-pressure pump bypass control valve, an LNG storage tank, an LNG submersible pump, and an LNG deep well pump. The LNG deep well pump and the LNG submersible pump are arranged in the LNG storage tank. The LNG storage tank is connected to the gas compressor through a pipeline. The gas compressor is connected to the gas cooler. A bypass is arranged on the side of the gas compressor and the gas cooler, and a compressor bypass control valve is arranged on the bypass. One end of the pressure regulating valve is connected to the gas cooler, and the other end of the pressure regulating valve is connected to the low-pressure gas buffer tank. The low-pressure gas buffer tank is connected to the third main gas valve, and the third main gas valve is connected to the dual-fuel boiler. The LNG deep well pump is simultaneously connected to the low-pressure pump bypass control valve, the high-pressure LNG reciprocating pump, and the low-pressure LNG evaporator. The low-pressure LNG evaporator is connected to the low-pressure gas buffer tank. The low-pressure gas buffer tank is connected to the second main gas valve, and the second main gas valve is simultaneously connected to the first dual-fuel power generation engine, the second dual-fuel power generation engine, and the third dual-fuel power generation engine. The high-pressure LNG reciprocating pump is connected to the high-pressure LNG evaporator. A bypass is arranged on the side of the high-pressure LNG reciprocating pump, and a reciprocating pump bypass control valve is arranged on the bypass. One end of the high-pressure gas buffer tank is connected to the high-pressure LNG evaporator, and the other end of the high-pressure gas buffer tank is connected to the first main gas valve. The first main gas valve is connected to the high-pressure dual-fuel main propulsion engine.

3. The dynamic simulation method of the gas equipment system based on digital twin technology according to claim 2, wherein Typical operating conditions include: The first typical operating condition: the stable operating condition of high-pressure gas at the maximum flow rate and the instantaneous switching from the stable operating condition of high-pressure gas at the maximum flow rate to the emergency gas cut-off condition; The second typical operating condition: the stable operating condition of low-pressure gas at the maximum flow rate and the instantaneous switching from the stable operating condition of low-pressure gas at the maximum flow rate to the emergency gas cut-off condition; The third typical operating condition: the stable operating condition of high-pressure and low-pressure gases simultaneously supplied at the maximum flow rate and the instantaneous switching from the stable operating condition of high-pressure and low-pressure gases simultaneously supplied at the maximum flow rate to the emergency gas cut-off condition; The fourth typical operating condition: the stable operation of high-pressure and low-pressure gases simultaneously supplied at the maximum flow rate is switched to the stable operation of high-pressure and low-pressure gases simultaneously supplied at the minimum flow rate; The specific process of the first typical operating condition includes: Start the LNG deep well pump or submersible pump, and use the LNG transported by the LNG deep well pump or submersible pump to pre-cool the high-pressure LNG reciprocating pump. When the temperature of the high-pressure LNG reciprocating pump is pre-cooled to below -130°C, start the high-pressure LNG reciprocating pump. The high-pressure dual-fuel main propulsion engine switches to gas operation, the main gas valve of the high-pressure dual-fuel main propulsion engine opens, the load of the high-pressure dual-fuel main propulsion engine is loaded to 100% load, and the high-pressure gas operates stably at the maximum flow rate. Furthermore, when the gas supply of the high-pressure dual-fuel main propulsion engine is suddenly cut off due to a fault, it switches to fuel mode operation; The specific process of the second typical operating condition includes: Start the LNG deep well pump or submersible pump, start the gas compressor, and the 3 low-pressure dual-fuel power generation engines and 1 low-pressure dual-fuel boiler are switched from fuel mode to gas operation one by one. The main gas valves of the power generation engines and the main gas valve of the boiler open. The loads of the 3 power generation engines are all adjusted to 70% load, and the load of 1 boiler is adjusted to 100% load. The low-pressure gas operates stably at the maximum flow rate. Furthermore, when the gas supply of the 3 power generation engines and 1 boiler is suddenly cut off simultaneously due to a fault, the 3 power generation engines switch to fuel mode operation, and 1 boiler stops operating; The specific process of the third typical operating condition includes: Start the LNG deep well pump or submersible pump, start the gas compressor, and the 2 low-pressure dual-fuel power generation engines and 1 low-pressure dual-fuel boiler are switched from fuel mode to gas operation one by one. The main gas valves of the power generation engines and the main gas valve of the boiler open. The gas operation loads of the 2 power generation engines are all adjusted to 55% load, and the gas operation load of 1 boiler is adjusted to 45% load. Use the LNG transported by the LNG deep well pump or submersible pump to pre-cool the high-pressure LNG reciprocating pump. When the temperature of the high-pressure LNG reciprocating pump is pre-cooled to below -130°C, start the high-pressure LNG reciprocating pump. The high-pressure dual-fuel main propulsion engine switches from fuel mode to gas operation, the main gas valve of the high-pressure dual-fuel main propulsion engine opens, and the load of the high-pressure dual-fuel main propulsion engine is loaded to 100% load. At this time, the high-pressure and low-pressure gases supply gas simultaneously and operate stably at the maximum flow rate. Furthermore, when the gas supply of the high-pressure dual-fuel main propulsion engine, 2 power generation engines and 1 boiler is suddenly cut off simultaneously due to a fault, the high-pressure dual-fuel main propulsion engine and 2 power generation engines switch to fuel mode operation, and 1 boiler stops operating; The specific process of the fourth typical operating condition includes: Start the LNG deep well pump or submersible pump, start the gas compressor, and gradually switch the 2 low-pressure dual-fuel power generation engines and 1 low-pressure dual-fuel boiler from the fuel mode to gas operation. Open the main gas valves of the power generation engines and the main gas valve of the boiler. Adjust the gas operation load of the 2 power generation engines to 55% load and the gas operation load of 1 boiler to 45% load. Use the LNG transported by the LNG deep well pump or submersible pump to pre-cool the high-pressure LNG reciprocating pump. When the temperature of the high-pressure LNG reciprocating pump is pre-cooled to below -130°C, start the high-pressure LNG reciprocating pump. Switch the high-pressure dual-fuel main propulsion engine from the fuel mode to gas operation, open the main gas valve of the high-pressure dual-fuel main propulsion engine, and load the high-pressure dual-fuel main propulsion engine to 100% load. At this time, the high-pressure and low-pressure gas are supplied simultaneously and operate stably at the maximum flow rate; furthermore, 1 power generation engine and 1 boiler are simultaneously cut off from gas due to a fault instantaneously. This power generation engine is switched to fuel mode operation, and this boiler stops operating. Adjust the gas operation load of the high-pressure dual-fuel main propulsion engine to 10% load, and adjust the gas operation load of the other power generation engine to 40%. At this time, the high-pressure and low-pressure gas are supplied simultaneously and operate stably at the minimum flow rate.

4. The dynamic simulation method of the gas equipment system based on digital twin technology according to claim 3, characterized in that, The initial operating conditions are the initial set values for the operation of the dynamic simulation model of the gas equipment system, including the initial liquid level height, initial pressure, initial temperature of the LNG storage tank, ambient temperature, composition of LNG, composition ratio of the heat exchange medium water glycol in the LNG evaporator, the initial states of the gas equipment system and the gas-using equipment, and the load setting of the gas-using equipment.

5. The dynamic simulation method of the gas equipment system based on digital twin technology according to claim 4, wherein The generation of the adjustment strategy information based on the operation result parameter information of the typical operating conditions includes: Based on the dynamic simulation model of the gas equipment system, according to the working process of a certain operating condition selected from the typical operating conditions, input the initial operating conditions into the dynamic simulation model of the gas equipment system. Run the automatic control program of the gas equipment system through the PLC virtual simulator and perform real-time data exchange with the dynamic simulation model of the gas equipment system to update the dynamic simulation model of the gas equipment system and obtain the current operation result parameters of the dynamic simulation model of the gas equipment system under the current operating condition. Compare the current operation result parameters with the process design parameters of the same operating condition to obtain the current difference value of the current operating condition. If the current difference value does not meet the design limit value, analyze and obtain the adjustment strategy of the automatic control program of the gas equipment system under the current operating condition. Based on the operation result parameters of the dynamic simulation models of different typical operating conditions, analyze and generate multiple adjustment strategies for the automatic control program of the gas equipment system.

6. The dynamic simulation method of the gas equipment system based on digital twin technology according to claim 5, characterized in that The operation result parameters of the dynamic simulation model of the gas equipment system include the operation result parameters of the pressure and temperature of the gas supply from the gas equipment system to the gas-using equipment changing with time; from the operation result parameters of the pressure and temperature changing with time, obtain the steady-state values and instantaneous change values of the gas supply pressure and temperature.

7. The dynamic simulation method of the gas equipment system based on the digital twin technology according to claim 6, characterized in that, The optimal adjustment strategy of the automation control program for the gas equipment system includes performing a linear programming algorithm of the simplex method based on the multiple adjustment strategies, and through calculation and iteration until the optimal adjustment strategy of the automation control program is found.

8. The dynamic simulation method of the gas equipment system based on digital twin technology according to claim 7, characterized in that The closed-loop dynamic simulation platform includes loading the automation control program of the gas equipment system into a PLC virtual simulator, simulating a PLC controller through the PLC virtual simulator to run the automation control program of the gas equipment system, and performing real-time data exchange with the dynamic simulation model of the gas equipment system to form a closed-loop dynamic simulation platform; The closed-loop dynamic simulation platform is used to simulate the dynamic changes in the temperature and pressure of liquid-phase and gas-phase LNG occurring in the gas equipment system over time.

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